In recent years, digital printing has been a rapidly developing printing technique which adopts a way of directly inputting, processing, and printing data for printing. A digital printing device processes original data into dot-matrix data through a host, processes the dot-matrix data into data suitable for imaging (i.e., imaging data) through a control system, and then controls an imaging unit to directly form images from the imaging data. A common workflow for a digital printing device of on-demand inkjet printing is: when a printing substrate (e.g., paper) reaches a predetermined position, under the control of the control system, a piezoelectric crystal in a printhead of the imaging unit will generate pulses to extrude inks, and directly eject mist ink droplets toward a surface of the printing substrate to form images.
In a large-scale printing production using a digital printer, it is usually required during printing to pause a printing device and change a new paper roll to continue printing due to the limited length of paper roll. There is an problem of chronological order of printing (the firstly printed page is taken as a front side and the later printed page is taken as a back side regardless of the contents thereof) during printing due to different physical arrangement positions of the printhead for printing images on the front side and the printhead for printing images on the back side. Therefore, when controlling pauses in printing of a digital printer, not only it is necessary to ensure that the number of printed pages of both images on the front side and images on the back side are identical when the printing is paused, but also it is necessary to ensure that images on the front side and images on the back side continue to output a new page following the particular page number when the printing is paused after the printing is resumed, that is, to ensure that images on the front side as well as images on the back side can be well aligned, and the numbers of printed pages are continuous without missing or repeating a page during the process of pausing and resuming printing.
In the prior art, the transmission of data to a back-end data receiving unit is stopped in order to pause data printing when the host finds a cause of pausing (e.g., the user commands to pause printing).
The inventors find that at least the following problems exist in the existing technique of pauses of printing: a certain amount of data will be buffered in the storage space of the data receiving unit of the printer, and after the host stops transmitting data, the printer can truly stop printing only after finishing printing the buffered data in the data receiving unit, that is, the existing pause function has a certain degree of lag: if the host has already transmitted all data to be printed presently to the data receiving unit of the printing system, the pause operation can be no longer possible, in other words, even it is paused, the printer can only stop printing actually after finishing printing all current job data, and thus a true pause function cannot be realized.